Unlike, its predecessor the FMP-X1, the FMP-X10 version of the Sony Ultra HD Media Player was supposed to work with any 4K TV that supported HDMI 2.0 and HDCP 2.2.
After being excited to try the FMP-X10 with my new Vizio M-Series 4K Ultra HD Smart TV, I was happy to see great quality 4K video finally...but with no audio. Despite being able to play both video and audio with no problem over HDMI 2.0 using other sources to the same HDMI 2.0 port of the Vizio TV, the Sony Media Player just would not play any audio coming from its own 4K movies, NetFlix, music library, etc.
When calling Sony support, the Sony technical support person was not HDMI literate and eventually told me to call Vizio for help since it was Vizio's problem and not Sony's. Rather than keeping on arguing the point that video and audio was working from other sources, just not Sony, I realized I wasn't going to get any productive help from Sony and hung up.
Still, after struggling to get true 4K working on my Vizio TV, I was actually happy to enjoy really good 4K resolution and crispness of the free movie Air Racers from the Sony Ultra HD Media Player. Just enjoying the sound of silence.